From 7d011962afbaa6e572cd8e0dbb7abf773e166e64 Mon Sep 17 00:00:00 2001 From: Vince Weaver Date: Wed, 17 Oct 2012 13:04:33 -0400 Subject: [PATCH] perf/x86: Remove cpuc->enable check on Intl KNC event enable/disable x86_pmu.enable() is called from x86_pmu_enable() with cpuc->enabled set to 0. This means we weren't re-enabling the counters after a context switch. This patch just removes the check, as it should't be necessary (and the equivelent x86_ generic code does not have the checks). The origin of this problem is the KNC driver being based on the P6 one. The P6 driver also has this issue, but works anyway due to various lucky accidents. Signed-off-by: Vince Weaver Cc: Peter Zijlstra Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Cc: eranian@gmail.com Cc: Meadows Cc: Lawrence F Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1210171303290.23243@vincent-weaver-1.um.maine.edu Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_event_knc.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/cpu/perf_event_knc.c b/arch/x86/kernel/cpu/perf_event_knc.c index 73bcfbdedd50..f3a2af41552d 100644 --- a/arch/x86/kernel/cpu/perf_event_knc.c +++ b/arch/x86/kernel/cpu/perf_event_knc.c @@ -173,26 +173,22 @@ static void knc_pmu_enable_all(int added) static inline void knc_pmu_disable_event(struct perf_event *event) { - struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); struct hw_perf_event *hwc = &event->hw; u64 val; val = hwc->config; - if (cpuc->enabled) - val &= ~ARCH_PERFMON_EVENTSEL_ENABLE; + val &= ~ARCH_PERFMON_EVENTSEL_ENABLE; (void)wrmsrl_safe(hwc->config_base + hwc->idx, val); } static void knc_pmu_enable_event(struct perf_event *event) { - struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); struct hw_perf_event *hwc = &event->hw; u64 val; val = hwc->config; - if (cpuc->enabled) - val |= ARCH_PERFMON_EVENTSEL_ENABLE; + val |= ARCH_PERFMON_EVENTSEL_ENABLE; (void)wrmsrl_safe(hwc->config_base + hwc->idx, val); } -- GitLab